LVT flooring usually comprises a transparent wear layer which may be coated by a UV cured PU lacquer, a decorative plastic foil and one or several core layers which generally are of different density and hardness. Relevant parts of this prior art description are also a part of the invention.
Thin LVT floors with a thickness of 2-3 mm have traditionally been installed by gluing to the sub floor. Recently LVT floors have been introduced on the market that comprises a mechanical locking system, which allows a floating installation without glue. This facilitates installation and eliminates a lot of work to prepare the sub floor for gluing.
Such LVT floors have generally a thickness of about 5 mm. This thickness is mainly required in order to form the locking system. The panel itself is strong and flexible and a thickness of about 3 mm would in many application be sufficient but can not be used since it is not possible to form a strong and cost efficient locking system in such thin floors.
Such problems related to minimum thickness requirements due to the forming of locking systems are also applicable in other thin floor panels such as laminate floors and wood powder based floors where material and weight savings may be accomplished with lower thicknesses, preferably below 6 mm.
Laminate flooring usually comprise a core of a 6-12 mm fibre board, a 0.2-0.8 mm thick upper decorative surface layer of laminate and a 0.1-0.6 mm thick lower balancing layer of laminate, plastic, paper or like material. A laminate surface comprises melamine-impregnated paper. The most common core material is fibreboard with high density and good stability usually called HDF—High Density Fibreboard. Sometimes also MDF—Medium Density Fibreboard—is used as core.
Laminate floor panels of this type have been joined mechanically by means of so-called mechanical locking systems. These systems comprise locking means, which lock the panels horizontally and vertically. The mechanical locking systems are usually formed by machining of the core of the panel. Alternatively, parts of the locking system can be formed of a separate material, for instance aluminium or HDF, which are integrated with the floor panel, i.e. joined with the floor panel in connection with the manufacture thereof.
The main advantages of floating floors with mechanical locking systems are that they are easy to install. They can also easily be taken up again and used once more at a different location.